Duct-forming device and method



p 1929 T. E. MURRAY DUCT FORMING DEVICE AND METHOD Filed May 21, 1924 Patented Sept. 24 1929 UNITED stares Parent orrice racemes. MURRAY, or nnoonmm, new "roan nucr-ronmzrne DEVIGE arm Mn'rnon Application filed ma at, rear. serial No; 714,958;

. In certain previous applications for patent rounding concrete and provided with flange-s I have described methods and apparatus for adapted to straddle the duct molds 2. Gypforming ducts in ,c'oncrete'floors, walls and sumis proposed because it is white and beother structuresin which ducts electric cables cause it can be easily broken out and re- 5 or Wires are to be carried, and which ducts moved so as to leave the desired s ace 55 maybe used for a variety of'other purposes. for making connections with the cables. The principal part of such apparatus is one Various other substances might be used, howor more rubber tubes which by their fiexiever, and the exposed portions thereof paintbility and their contractibility in cross-seced, if necessary, to make a contrast with the lotion can be used as forms or molds about concrete. Preferably the block 4 has an into which the concrete is poured and can be subtegral button 6 extending upward to the level sequently pulled out, leaving ducts extending of the top of the concrete, and this button in any desired directions through the floor alone is exposed. It makes a largeenough or other structure. The form being covered opening inthe concrete, however, for access by the concrete, it is important to know, after to and withdrawal or the parts of the re- 65 the floor is completed, where the duct is 10- movable block 4. cated. For this purpose I have invented in use the blocks will be placed in the mant i markers hi h t only locate the ner indicated in the drawing at desired points line of the duct but also facilitate the proin the lengths of the tubes. The concrete vision of openings from the surface of the of the wall will thereafter be poured to the 70 floor to the duct at desired points. level of the contrasting buttons 6. When the The accompanying drawings illustratean floor has hardened the tubular forms 2 will embodiment of the invention. be withdrawn and the electric wires'inserted Fig. 1 is aperspective view, partly in secand connected up with the mains in the tion of a portion of a floor; usual way. Whcna connection is. desired to 75 Fig. 2 is a perspective View of one or the an apparatus in the building, the nearest markers used. button '6 1S gouged outwith a sharp tool.

Referring to the accompanying drawings, Preferably also the entire block 4.- with its the floor is made of a body of concrete flanges 5 is broken n and removed so as to so molded about lines of tubing 2 intended to give access to e wires in the ducts. to be subsequently withdrawn to leave the con-- These wires may be drawn up through the duits throughwhich the wires are to be holes left by the button 6 and the desired passed. Removable forms 3 are provided to connections made thereto and the wires mold junction boxes which are to cornniuni pushed back into the duct.

e5 cate with the ducts. Though l have described with great paras It is desirable also to have openings ticularity of detail a certain embodiment various points along the length oi the ducts of my invention, yet it is not to be underthrough which connections may be made stood therefrom that the invention is re lamps, heaters or other apparatus. stricted to the particular embodiment dis- 40 At points where such connections can be closed l1 arious medications may be made he most conveniently made, markers are located by skilled in the art without dewhen the tubing is laid in position and are partnre from the invention as defined in built into the concrete in such a as to the following claims. be visible when the concrete floor is com slain-i is- 4:5 pleted.- Preferably also such markers con '1. A device the character described for as stitute a sort of removable molds for open use in connection with duct molds conipris ings leading to the ducts. ing a bod dapted such mold and In the case illustrated themarlter consists having a frangible portion extending to the of a block 4 of gypsum or similar frangible of the structure in which the duct is material of color contrasting the sun to be termed. ice

2. The method of forming concrete floors and similar structures with ducts whichineludes the steps of positioning, a duct mold and a marker extending to the level of the floor surface and casting the concrete about the mold and marker and up to said level, and withdrawing the mold without the marker.

3. The method of forming molded structures with a duct therein having an outlet which comprises locating a duct mold and a frangible marker extending therefrom to the outer'surface of the structure and casting concrete about the mold and marker and to said outer surface, and withdrawing'the mold and breaking said marker out of the surrounding concrete.

4. A combined outlet mold and marker for use with molded ducts in concrete building slabs, comprising a core of frangible material extending from the interior of the molded duct to the surface of the slab.

- .5. A concrete building slab having a duct therein and a frangible marker extending from an intermediate point in the length of the duct to the surface of the slab to mark the location of the duct and -to provide easy access thereto by gouging out the marker.

In witness whereof, I have hereunto signed my name.

THOMAS E. MURRAY. 

